Abstract: Objective:To investigate the effects of compression treatment on occurrence of seroma after tension-free inguinal hernia repair.
Methods:The propensity score matching and retrospective cohort study was conducted. The clinical data of 6 600 patients with unilateral inguinal hernia who were admitted to 51 medical centers from January to December in 2017 were collected, including 917 in Beijing Chaoyang Hospital of Capital Medical University, 451 in East Hospital Affiliated to Tongji University, 363 in Huadong Hospital of Fudan University, 307 in Ruijin Hospital of Shanghai Jiaotong University School of Medicine, 254 in Sir Run Run Shan Hospital of Zhejiang University School of Medicine, 222 in Sichuan Provincial People′s Hospital, 221 in Beijing Luhe Hospital of Capital Medical University, 202 in Shengjing Hospital of China Medical University, 191 in Anhui Provincial Hospital, 181 in Affiliated Hospital of Zunyi Medical University, 174 in Tianjin People′s Hospital, 169 in the First Affiliated Hospital of Dalian Medical University, 155 in People′s Hospital of Changshou in Chongqing, 152 in Qilu Hospital of Shandong University, 146 in the First Affiliated Hospital of Fujian Medical University, 136 in Taiyuan Central Hospital of Shanxi Medical University, 134 in First Hospital of Wuhan, 122 in Xinjiang Uygur Autonomous People′s Hospital, 122 in the Second Affiliated Hospital of Chongqing Medical University, 118 in the Second Hospital Affiliated to Naval Medical University, 113 in Xuzhou Central Hospital, 112 in the First Affiliated Hospital of Harbin Medical University, 112 in the First Affiliated Hospital of Wenzhou Medical University, 102 in the Second Hospital of Shandong University, 100 in Tianjin Hospital of Itcwm Nankai Hospital, 99 in Shandong Provincial Hospital, 90 in Huashan Hospital of Fudan University, 88 in Henan Provincial People′s Hospital, 87 in West China Hospital of Sichuan University, 86 in Zhangjiakou First Hospital, 86 in the First Affiliated Hospital Soochow University, 77 in the Fourth Affiliated Hospital of China Medical University, 75 in Tianjin Medical University General Hospital, 72 in the First Affiliated Hospital of Hunan University of Medicine, 67 in First Affiliated Hospital of Xi′an Jiaotong University, 49 in the First Hospital of China Medical University, 49 in Hunan Provincial Hospital of Traditional Medicine, 48 in Xijing Hospital Affiliated to Air Force Medical University, 47 in Xinhua Hospital of Hubei Province, 46 in the First Hospital of Tsinghua University, 45 in the First Affiliated Hospital of Chongqing Medical University, 34 in the First Affiliated Hospital of Zhengzhou University, 29 in Peking University International Hospital, 28 in Jilin Yan′an Hospital, 25 in China-Japan Union Hospital of Jilin University, 22 in Peking University Third Hospital, 22 in Peking University First Hospital, 20 in the Fourth Affiliated Hospital of Harbin Medical University, 19 in Chengdu Fifth People′s Hospital, 8 in Chinese PLA General Hospital, 6 in Taikang Xianlin Drum Hospital. There were 5 850 males and 750 females, aged (57± 16)years, with the range from 18 to 92 years. Of the 6 600 patients, 4 939 with compression treatment after tension-free inguinal hernia repair were divided into compression group and 1 661 without compression treatment after tension-free inguinal hernia repair were divided into non-compression group. Observation indicators: (1) the propensity score matching conditions and comparison of general data between the two groups after matching; (2) compression treatment of patients in the compression group after matching; (3) occurrence of seroma after tension-free inguinal hernia repair in the two groups after matching; (4) analysis of influencing factors for seroma after tension-free inguinal hernia repair. Follow-up using outpatient examination was performed at postoperative 14 days and 30 days to detect occurrence of seroma after tension-free inguinal hernia repair of patients up to January 2018. The propensity score matching was realized using the nearest neighbor method with 1∶1 ratio and caliper setting as 0.01. Measurement data with normal distribution were represented as Mean±SD, and comparison between groups was analysed using the t test. Measurement data with skewed distribution were represented as M (P25, P75) or M (range), and comparison between groups was analysed using the Wilcoxon rank sum test. Count data were described as absolute numbers or percentages, and comparison between groups was analysed using the chi-square test. Univariate analysis and multivariate analysis were conducted using the Logistic regression model.
Results: (1) The propensity score matching conditions and comparison of general data between the two groups after matching: 3 322 of 6 600 patients had successful matching, including 1 661 in each group. Cases with smoking history, cases with coronary heart disease, cases with diabetes, cases with reducible hernia, irreducible hernia, incarcerated hernia, strangulated hernia (hernia grading), cases with Lichtenstein repair, cases with transabdominal preperitoneal patch repair, totally extraperitoneal repair(surgical methods), operation time, cases with emergency operation before propensity score matching were 1 110, 273, 333, 4 606, 63, 262, 8, 1 636, 2 515, 788, 60 minutes(50 minutes, 90 minutes), 155 in the compression group, and 233, 55, 87, 1 572, 28, 57, 4, 478, 941, 242, 60 minutes(45 minutes,80 minutes), 29 in the non-compression group, respectively, showing significant differences in the above indicators between the two groups (x²=54.713, 12.927, 4.721, 11.218, 16.656, Z=-7.598, x²=8.891, P<0.05). After propensity score matching, the above indicators were 231, 63, 82, 1 579, 20, 61, 1, 526, 826, 309, 60 minutes(45 minutes, 81 minutes), 34 in the compression group, and 233, 55, 87, 1 572, 28, 57, 4, 478, 941, 242, 60 minutes(45 minutes,80 minutes), 29 in the non-compression group, respectively, showing no significant difference in the above indicators between the two groups (x²=0.018, 0.624, 0.157, 0.159, 0.240, Z=0.001, x²=0.468, P>0.05). (2) Compression treatment of patients in the compression group after matching: of the 1 661 patients in the compression group after matching, 968 underwent compression treatment with 0.5 kg of sandbag or 500 mL of packed 0.9% sodium chloride solution, 109 underwent compression treatment with trusses, 112 underwent compression treatment with girdles, 311 underwent compression treatment with elastic underwear and 161 underwent compression treatment with elastic underwear combined with 0.5 kg of sandbag. (3) Occurrence of seroma after tension-free inguinal hernia repair in the two groups after matching: patients of the two groups after matching were followed up at postoperative 14 days and 30 days. Occurrence of seroma after matching were 44 and 15 in the compression group and non-compression group, respectively, showing a significant difference between the two groups (x²=13.299, P<0.05). (4) Analysis of influencing factors for seroma after tension-free inguinal hernia repair. Results of univariate analysis showed that cases with direct inguinal hernia, cases undergoing compression treatment with 0.5 kg of sandbag or 500 mL of packed 0.9% sodium chloride solution were related factors for occurrence of seroma after tension-free inguinal hernia repair (odds ratio=0.518, 4.689, 95% confidence interval: 0.271-0.989, 2.730-8.055, P<0.05). Results of multivariate analysis showed that compared with no compression treatment, cases undergoing compression treatment with 0.5kg sandbag or 500 mL pack of 0.9% sodium chloride solution was an independent risk factor for occurrence of seroma after tension-free inguinal hernia repair (odds ratio=4.698, 95% confidence interval: 2.734-8.073, P<0.05).
Conclusion:Compared with no compression treatment, cases undergoing compression treatment with 0.5 kg of sandbag or 500 mL of packed 0.9% sodium chloride solution is an independent risk factor for occurrence of seroma after tension-free inguinal hernia repair.